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Hi Jack, I think you bring up a good point , thanks! The <0.5W for 8 x retiming function is a measured result now. The module total power estimates of 3 W is a recent Finisar prediction for a QSFP+ form factor 100GBASE-SR4, which does assume the lower power retime function. I think it’s also worth saying that some things don’t scale well with process node, for example VCSEL bias and modulation current, TIA SNR and overload requirements, don’t scale with transistor size…. Best wishes jonathan From: Jack Jewell [mailto:jack@xxxxxxxxxxxxxx] Hey Jonathan/Ryan, On slide 6, there is a list of electronically-performed functions. After CDR power consumption decreases over time, its power consumption is still close to 0.5W, which is significant. It isn't directly compared with the power consumed by the other electrical functionst, just inferred on the "Size" slide 9. Are those total powers estimated using today's values for the other functions, or using similarly-projected power-reduced values? I.e. should the powers for the 100m and 20m reach modules on slide 9 be closer to 2.5W and 2.0W, or even 2.0W and 1.5W? Makes a difference for the percentage power consumed by CDR. Thanks, Jack From: Jonathan King <jonathan.king@xxxxxxxxxxx> Dear all , Ryan and I are seeking supporters and detractors for the attached joint presentation: “Cost, power, size differences of proposed MMF PMDs: 20 m reach un-retimed vs 100 m reach retimed baseline”, which will be submitted for to the May meeting of 802.3bm in Victoria, BC. The slides conclude that “• By about the same time 802.3bm is technically stable (H2 2014) there will be no significant power, cost, or size, advantage to be gained from an un-retimed short reach PMD. – A 20 m reach un-retimed PMD would not meet the criteria for distinct identity. • The 20 m reach objective is met by the 100 m reach PMD, a separate 20 m PMD is not required” If you agree (or disagree) with the presentation and wish to be listed as a supporter (or detractor) of the presentation, please let me know by e-mailing me. Thanks ! Best wishes jonathan |